Technical Field
The present disclosure relates generally to a surgical instrument for applying surgical staples to body tissue. More particularly, the present disclosure relates to a surgical stapling instrument suitable for performing circular anastomosis and/or treatment to internal walls of hollow tissue organs.
Background of Related Art
Anastomosis is the surgical joining of separate hollow organ sections. Typically, an anastomosis procedure follows surgery in which a diseased or defective section of hollow tissue is removed and the remaining end sections are to be joined. Depending on the desired anastomosis procedure, the end sections may be joined by either circular, end-to-end, end-to-side, or side-to-side organ reconstruction methods.
In a circular anastomosis procedure, the two ends of the organ sections are joined by means of a stapling instrument which drives a circular array of staples through the end section of each organ section and simultaneously cores any tissue interior of the driven circular array of staples to free the tubular passage. Examples of instruments for performing circular anastomosis of hollow organs are described in U.S. Pat. Nos. 7,303,106; 6,053,390; 5,588,579; 5,119,983; 5,005,749; 4,646,745; 4,576,167; and 4,473,077, each of which is incorporated herein in its entirety by reference. Typically, these instruments include an elongated shaft having a handle portion at a proximal end to actuate the instrument, an anvil retainer, and a staple holding component disposed at a distal end. An anvil assembly including an anvil rod with attached anvil head is mounted to the distal end of the instrument adjacent the staple holding component. Opposed end portions of tissue of the hollow organ(s) to be stapled are clamped between the anvil head and the staple holding component, via the anvil retainer. Typically, a first actuation mechanism is used to approximate the anvil head and the staple holding component to clamp the tissue. The clamped tissue is stapled by driving one or more staples from the staple holding component so that the ends of the staples pass through the tissue and are deformed by the anvil head. Typically, a second actuation mechanism is used to fire the staples. It is also common for an annular knife to be concurrently advanced to core tissue within the hollow organ to free a tubular passage within the organ.
Upon engaging the first actuation mechanism and approximating the anvil head and staple holding component, the anvil rod must pass through the aperture made in the tissue where the anvil retainer passed through. The problem typically arises that the aperture diameter made by the anvil retainer is too small for the anvil rod to pass through. As a result, excess tissue is pulled into the device when approximating the anvil head. Furthermore, the tissue in some procedures is tied to the trocar by a suture. The suture can fail to slide over the anvil during retraction, also leading to too much tissue being pulled into the device. Accordingly, a need exists for a device to prevent the excessive build up of tissue which is pulled into the device, specifically, a device for enabling the anvil head to pass through the aperture made by the anvil retainer.